1. Field of the Invention
The invention relates to a laminated glass pane having at least one rigid glass sheet and one sheet of a flexible plastic material, particularly a glass pane produced in limited-run series production and having a peripheral strip. The invention also relates to a method of manufacturing such a glass pane.
2. Discussion of the Background
Glass panes used in the aircraft sector, the railroad sector, and/or tinted and/or shielded glass panes, heated windshields, and in general glass panes requiring special fabrication, are manufactured in limited-run series production.
If these laminated panes contain two rigid sheets as the exterior sheets they may be called symmetric, whereas panes in which one of the exterior sheets is rigid and the other is comprised of a flexible plastic material may be called asymmetric.
Flexible plastic sheets which are components of a laminated pane are intended to improve the properties of the pane. For example, a polyurethane plastic material may be used for an exterior sheet to confer surface properties such as scratch resistance, anti-sharding protection, etc. Sheets of polyurethane, polyvinyl butyral, or other materials may be used as intermediate sheets: in particular, a polyvinyl butyral intermediate sheet improves the shock absorption of the pane.
Assembly in limited serial production of the sheets which are components of a glass pane ordinarily involves the following steps. First, the sheets are placed in a hermetically sealed bag, under vacuum. The bag is placed in an autoclave having an interior pressure of 8 to 14 bar, with a temperature of 100.degree. to 140.degree. C. During the autoclaving, the plastic material tends to flow under the influence of the elevated temperature, whereby it may leak out over the edge of the pane.
After assembly, a mastic which provides a finish and/or protection is ordinarily applied to at least a part of the periphery of the pane. The process of applying this mastic is lengthy, requiring a number of stages:
application of masking means to the regions which are not to be coated with the mastic (particularly the border regions of the faces of the exterior sheets), PA1 application of the mastic, PA1 final configuration of the mastic with a putty knife or the like, and PA1 removal of the masking means. PA1 an internal layer comprised of a material the softening temperature of which is less than or equal to the temperature employed in the autoclaving of the sheets which are components of the pane, and PA1 an external layer comprised of a material the softening temperature of which is greater than the temperature used in the autoclaving of the sheets. The peripheral strip may be at least temporarily held over the pane with the aid of appropriate means such as, in particular, adhesive band(s). These means are removed after the assembly, the peripheral strip now being fixed to the pane with the aid of, in particular, the internal layer.
Further, a step in which the mastic is polymerized is required.